Time-delay relay



March 17, 1953 A. B. POOLE 2,631,664

T1MEDELAY RELAY Filed June 4, 1951 5 sheets-sheet 1 i .l 3T, 9192/575; or/z.

zg-022 Q5 a ,i4

l li' 'f V Ivlllllillll'! JNVENTOR. ARTH UR B. POOLE March 17, 1953 A.B. POOLE 2,631,664

TIME-DELAY RELAY Filed June 4, 195] 5 Sheens-Sheetl 2 INVENTOR. 7g3ARTHUR B. POOLE Y B @M5 ,6m-w

March 17, 1953 A. B. POOLE 2,631,664

TIME-DELAY RELAY Filed June 4, 1951 5 sneeis-sneet 5 f3 w um?? OEE gcusm, Q wb INVENTOR. ARTHUR B. POOLE Wwf@ March 17, 1953 Filed June 4,1951 A. B. POOLE 2,631,664

TIME-DELAY RELAY 5 Sheets-Sheet 4 r SN? G INVENTOR. ARTHUR B. P OOLE MfwMarch 17, 1953 A. B. POOLE 2,631,664

TIME-DELAY RELAY Filed June 4, 195] 5 Sheets-Sheet 5 JNVENTOR. \0 ARTHURB. POOLE Q BY l Patented Mar. 1.7, 1953 TIME-DELAY RELAY Arthur B.Poole, Harwinton, Conn., assigner to Haydon Manufacturing Company, Inc.,Torrington, Conn., a corporation of Connecticut Application .l' une 4,1951, Serial No. 229,774

Claims.

The present invention relates to electrical relays, and, moreparticularly, to an improved motor driven time delay relay which issuitable for establishing or interrupting circuit connections to acontrolled circuit for a predetermined time interval after energizationof the relay.

In relays of the character described, it is customary to use a small,relatively inexpensive, constant speed synchronous motor as a powersource for driving the timing mechanism of the relay whereby accuratelycontrolled and long time delays are possible. However, such a motor isof relatively low power output with the result that the contact pressureavailable to close the relay switch contacts is relatively small. Also,when the driving motor operates the switch contacts directly, the speedof contact closure is dependent upon the motor speed and is necessarilyrelatively slow in most applications. Certain arrangements heretoforeproposed have provided a ilexible switch member which is stressed whenthe relay is energized to store sufficient energy therein to permitrapid and positive closure of the switch contacts at the end of the timedelay interval. In general, however, such prior relay structures are notcapable of being immediately reset, due to improper meshing of thegears, or the like, are usually quite complicated structurally, and areso designed as to require an inordinate mounting space.

Accordingly, it is an object of the present invention to provide a newand improved time delay relay of the character described.

It is a further object of the present invention to provide a new andimproved time delay relay which may be substantially immediately resetto its initial position and wherein a low power driving motor may beemployed.

It is another object of the present invention to provide a new andimproved time delay relay wherein a low power driving motor may beemployed and the time delay interval may be conveniently adjusted bymanually operable means.

Still another object of the present invention is to provide a new andimproved time delay relay wherein a low power driving motor may beemployed and the time required to reset the relay may be convenientlyadjusted by manually operable means.

Another object of the present invention resides in the provision of atime delay relay wherein a low power driving motor may be employed andthe timing gears remain in mesh throughout the relay cycle to facilitatesubstantially immediate resetting of the relay.

It is another object of the present invention to provide a new andimproved low power input time delay relay which is of simple andeconomical construction, is small in size, and requires only a smallamount of space.

It is still another object of the present invention to provide anintegrating time delay relay which requires a relatively low powerdriving motor and wherein the relay is substantially immediately resetat the end of a predetermined time delay interval.

A further object of the present invention resides in the provision of anew and improved time delay relay wherein the total time delay may beautomatically increased or decreased in accordance with a second signalwhich occurs after the relay is first operated.

Further objects and advantages of the present invention will becomeapparent as the following description proceeds and the features ofnovelty which characterize the invention will be pointed out withparticularity in the claims annexed to and forming a part of thisspecification.

For a better understanding of the present invention, reference may behad to the accompanying drawings in which:

Fig. 1 is a front elevational view of one embodiment of a time delayrelay embodying the present invention;

2 is a rear elevational view of the relay of Fig. 3 is a view taken inthe direction of the arrows 3 3 of Fig. 1;

Fig. 4 is a view taken in the direction of the arrows 4 4 of Fig. 1;

Fig. 5 is an enlarged sectional view taken on line 5 5 of Fig. 1;

Fig. 6 is a sectional view taken on line 6 6 of Fig. 5, assuming thatFig. 5 shows the complete structure;

Fig. 7 is a fragmentary view looking in the direction of the arrows 1 1of Fig. 5, and assuming Fig. 5 shows the complete structure;

Fig. 8 is an enlarged top view of Fig. 1;

Fig. 9 is a front view on a larger scale of the relay of Fig. 1 withportions thereof partially broken away;

Fig. 10 is a somewhat distorted perspective view of the relay of Fig. 1shown connected in an electrical circuit in order to aid inunderstanding the operation of the relay in performing certain controlfunctions with respect to a load circuit; and

Figs. 1l and 12 are views similar to Fig. 10 of alternative embodimentsof the relay of the present invention.

Briey, in accordance with one aspect of the invention, the time delayrelay includes a con- 3 stant speed electric motor which is adapted todrive a differential gear train including a normally stationarydifferential cage. An electromagnetic relay having an armature normallybiased away from the coil thereof is provided and the relay and motorare smul-taneously energized at the start of the time delay interval. Aswitch actuating spring carried by the relay armature is restrained bylatch means whereby the armature stresses the spring when the relay isoperated. Also, when the relay is operated the driven gear of thedifferential gear train is held stationary so that the differential cageis rotated in a predetermined path so as to engage the latch means aftera predetermined time delay interval to trip the latch means therebyreleasing the switch actuating spring and modifying connections to acontrolled time delay circuit. Movement of the differential cage beyondthe latch trip position causes the motor to be deenergized and when thecontrolling circuit is opened both the differential cage and latch meansare returned to their respective initial positions. In accordance with afurther aspect of the invention the time delay interval is convenientlyadjusted by adjusting the normal stationary position of the differentialcage. Furthermore, the return time of the differential cage may beadjusted to obtain a predetermined reset interval.

Referring now to the drawings, and more particularly to Figs. l to 10,inclusive, thereof, the present improved relay is therein illustrated asgenerally comprising a mounting plate ifi on one side of which ismounted a small self-starting synchronous motor l! which is adapted tobe energized from a suitable single phase source more fully describedhereinafter. also supported from the same side of mounting plate te isan electromagnet indicated generally at i2. On the other side of themounting plate lll there is provided the time delay mechanism indicatedgenerally at i in Fig. 5 of the drawings. The driving motor il may be ofrelatively low power output and includes a standard gear reductionmechanism indicated generally at i3 which reduces the speed of the motordrive shaft and provides a relatively low speed output shaft id (Figs. 5andr 10) suitable for driving the timing mechanism I5.

As best shown in Figs. 3 and 7 of the drawings, the electromagnet l2includes a core stucture I8 which is made up of E-shaped laminations onthe center leg of which there is positioned the coil I9. An armature 2liis hinged by means of the pin 2| to one leg of the core i8 and isnormally biased away from the coil i9 by means of the coil spring 22.

Generally considered, the time delay mechanism l5 includes a triangularshaped back plate 30 which is separated and supported from the mountingplate I by means of the spacers 3i and mounting screws 32 respectively.The back plate 30 supports a bearing 34 in which is journaled one end ofa timing shaft 35, the other end of which is journaled in the mountingplate it. The timing shaft 35 carries a driving gear 36 fastened theretowhich meshes with a driving pinion 31 rotatable with the motor driveshaft it. The timing shaft 35 also carries adiilerential cage 38rotatable thereon which iny turn carries the differential gears 39Aandvll which are fixed except for rotationabout theiraxes relative tocage 38. A driven gear 4l is secured by means of a hub 42 to a ratchetwheel 43, and the driven gear 4I and ratchetv wheel i3 are all adaptedto rotate about the timing shaft 35 just as is the cage 38.

As best illustrated in Figures 5, 6, and 9, the differential cage 38comprises a relatively flat plate 45 which is mounted on the shaft 35for rotation thereabout and is counter-balanced on one end by means ofan arcuate counter weight fit rigidly attached thereto which offsets theweight of the differential gears 39 and il carried by the plate 135. Theplate 45 is provided with a recess li'l adapted to receive thedifferential gears 3d and it and these gears are mounted between opposedear portions 159 and El) of the mounting plate 153 by means of the pins5i and 52. The differential gears 39 and 46 mesh with each other asshown at S3 (Fig. 6) While the gear 39 also meshes with the driven geardl, and the gear 4i) meshes with the driving gear 36.

The timing shaft bearing 34 also carries a toothed adjustment wheelwhich may be r0- tated by means of an adjustment pinion Eid which mesheswith the wheel 55 and may be adjusted by means of an adjustment screw lavailable at the outside of back plate 30. The adjustment wheel 5:3 isbiased against the back plate 30 through the spacer 53 by means of vaconical friction spring di) which is carried on the inner portion of the4bushing 3d and effectively presses the adjustment wheel 55 against theback plate 3d so as to maintain this wheel stationary during the timedelay operation.

In order to control the initial position of the differential cage 33,the adjustment wheel 55 is provided with a iiat side G2 (Fig. 1) towhich there is secured a projecting arm 63 which acts as a stop for thedierential cage 38. More specifically, the differential cage 3S isprovided with a projecting arm 64 which extends beyond the stop arm 63and the differential cage is normally biased against the stop arm 63 bymeans of a coil spring 6B which is secured at one end to one of thespacers 3| and extends around and is secured to a grooved bushingBS'which is positioned on the timing shaft 35 and fastened lto the cage33. Thespring 66 thus biases the differential cage 38 clockwise asviewed in Fig. 9 so that the arm S4 thereof is normally held against thestop arm 63 as indicated in Fig. l of the drawings.

For the purpose of holding'thedriven gear vil! of the differentialgearing stationary so that the differential cage 38 can be rotatedduring the time delay interval, there is provided a ratchet pawlindicated generally at 'iii which is rotatably mounted on the pawl shaft'il and is vprovided with teeth 'i2 adapted to mesh with the teeth onthe ratchet wheel liti. The position of the pawl iii on the shaft 'il isdetermined by a pawl bushing 69 which is press fitted on the shaft 'iiand the ratchet pawl 'ifi is Vnormally held against 'the bushing 69 andbiased into engagement with the ratchet wheel 43 by means of the torsioncoil spring i3 (Fig. .7) and is provided at one end thereof with a camear 'M which is positioned over an upstanding pin it carried by therelay armature 20. As mentioned above, the relay armature 28' isnormally biased away from the relay coil E9 by the spring 22 and in thispositionthe pin' l5 engages the ear portion 'l and cams the ratchet pawl'it away from the ratchet wheel t3 as is clearly' evident from'Fig. 5ofthe drawings. Accordingly, when the relay i2 is de-energized las shownin Figs. 3 and5, and the relay armature 2t is in itsuppermostposi- 5tion, the ratchet pawl 'I0 is disengaged fromV the ratchet wheel 3.

To establish electrical connection to a controlled time delay circuitthere is provided a switch mechanism indicated generally at 83 which ismounted on the mounting plate I directly above the above-described timedelay mechanism as viewed in Figs. 1 and 3 of the drawings. The switchmechanism 8B may comprise a set of normally open or a set of normallyclosed contacts depending upon the desired control. As illustrated theswitch mechanism 3D includes both a set of normally open and a set ofnormally closed contacts for more universal application and comprises apair of flexible switch blades 8| and 83 and a central switch blade 82(Fig. 8) which are embedded in the stacked insulator blocks 84, 85,

and @c and are secured in stacked relation to thev mounting plate it byany suitable means such as the supporting studs 81 and 88. The eXibleswitch blade Sl is provided intermediate the length thereof with aswitch contact 9B adapted to engage a complementary switch contact 9ipositioned on one side ci the central switch blade 82. Likewise theflexible switch blade S3 is provided with a switch contact 93 adapted toengage with a complementary switch contact Si. on the other side of thecentral switch blade 82.

In order to move the flexible switch blades 8i and 83 in unison relativeto the central blade 82 so that the switch contacts S?, SI and @2, d3may be opened and closed, there is provided a switch actuating member Q5of insulating material which is positioned between the ends of theswitch blades 8l and 83 and is provided with a portion 96 of reduceddiameter between the blades 8| and 83 (Fig. 7). The notch SI5 is adaptedto receive the biiurcated end 99 of a switch actuating spring Idil, theother end of the spring h'iil being secured to the hinged end of therelay armature 2t.

For the purpose of restraining the switch actuating spring when therelay armature 2d is closed whereby suicient energy may be stored in thespring Itli to cause rapid and positive actuation of the contacts 93',SI and 92, 93 upon the release of the actuating spring it, there isprovided a latch member m5 which is rotatably supported on a latch shaftI and is provided with a projecting arm portion IIl'I which is adaptedto t under the edge of a notch IGS (Figs. 9 and 10) in the side of theswitch actuating spring Iii. The latch H35 is seated on the upper end ofa latch bushing II! which is press tted on the shaft H35 and the latchis normally biased into engagement with the spring |00 by means of thetorsion spring i139 which also keeps the latch seated on the bushingIII. The latch |55 is adapted to be tripped by the differential cage 3Swhen the latter member has been rotated counterclockwise, as viewed inFig. 9 by an amount suicient to cause the cage 33 to strike the end I i9of the latch |05 and thus rotate the latch clockwise as viewed in Fig. 9to withdraw the arm portion IG'I thereof from beneath the spring Ill-iland release the spring. The time delay interval is thus equal to thetime required for the diferential cage 38 to travel from its initialposition, as determined by the position of the stop arm $3, to its latchtripping position at which time the switch contacts 92 and 93 are closedand the contacts 9B and 9| are opened.

To provide an indication of the time delay setting of the relay whilepermitting this time delay setting to be adjusted by means of theadjustment screw 5l, there is dened in the back `plate a viewing openingII (Fig. il'

through which is visible a circle of graduations I2 I inscribed-upon theadjustment wheelV 55. The graduations I 2i arecalibrated in terms of thetime delay intervals for different positions of the stop arm 63 and areference marker I22 is provided on the plate 3) to permit an accuratesetting of the time delay.

In order to deenergize the driving motor I I after the switch 8B hasbeen actuated and the desired circuit connections established, there isprovided a motor control switch indicated generally at |29 (Figs. 2 and10) which includes a generally U-shaped flexible switch blade ISB whichis normally engaged with a stationary switch contact ISI, the switchblade IBD and contact I3! being supported by suitable terminal bracketson a mounting plate I53 which is in turn supported on the plate I il. Toopen the motor switch contacts after the time delay interval iscompleted, a tripping arm 535 is provided which is secured to the latchbushing III and extends outwardly beyond the switch actuating springIllil as best illustrated in Figs. 2 and 9, and is adapted to engage anintermediate point on the flexible switch blade ISD when the latch i5 ismoved beyond its spring releasing position by the difierential cage 38.The operation of the time delay relay discussed above, can best beunderstood by reference to Fig. 10 of the drawings depicting a somewhatdistorted perspective view of the relay of Fig. l, and, moreover,illustrating this relay in a typical circuit application. Thecorresponding parts of Fig. l0 have been designated by the samereference numerals as in the preceding iigures. Referring to Fig. l0, itmay be observed that the incoming line terminals |46 and itl areconnected to energize both motor Il and the coil I9 of the electromagnetI2 in parallel. The line terminals are also connected to supply a loadcircuit which should be energized after a predetermined time delaythrough the normally open switch contacts 92-93 of switch Sil. When thesynchronous motor II is energized, it drives, through the gear reductionmechanism I3 thereof and through the motor drive shaft I4, the motorpinion 3'! in a clockwise direction as viewed in Fig. l0, which in turnrotates the driving gear and the timing shaft 35 in a counterclockwisedirection. The diierential cage 38, which is rotatably supported on thetiming shaft 35, is initially held stationary by engagement of the arm Sthereof with the stop arm 63 on the adjustment wheel 55, the engagementof these members being maintained by the direrential cage return spring66. With the differential cage 35 held stationary, rotation of thedriving gear 35 produces rotation of the difierential gear l0 in theclockwise direction, which in turn rotates the differential gear 39 inthe opposite direction so as to rotate the driven gear 4I and theratchet wheel t3 in the clockwise direction. However, such operationcontinues only until the relay armature 25 is in its fully attractedposition at which time the ratchet pawl IB engages the ratchet wheel i3and stops the driven gear 4I from rotating. When the driven gear 4I isheld stationary in the manner described above, the differential cage 38is then rotated in the counterclockwise direction, the differentialgears 39 and 4B being rotated along the peripheries of the rotatingdriving gear 3'5 and the stationary driven gear I respectively. As aresult, the diierential cage is moved in the direction shown by the.arrow following energization of the electromagnet I2 and when thearmature 20 thereof is in its fully attracted position.

When the electromagnet 2 is operated and the armature 20 thereof movesdownwardly under the attra-ction of the armature coil I9, the lswitchactuating spring |00, which is secured at one end to the relay armature20, is restrained by means of the latch |05 which is provided with theextension arm |07 positioned beneath the switch actuating spring |00,the latch |05 being biased into the spring engaging position by means ofthe spring IMI. The outer end of the switch actuating spring engages theswitch actuating member 95 of the switch mechanism .80. .In the positionshown in Fig. 10, the contacts 90 and 9| associated with the switchblades 8| and .82 are closed and the contacts 92 and 53 associatedrespectively with the switch blades 82 and 83 are opened. Accordingly,in the position shown in Fig. 10 the line circuit is open at the switch80 and the time delay load circuit M5 is deenergized.

When the diierential cage 38 is rotated in the manner described above toa point at which it engages the projecting arm I Iii of the latch member|05, this member is rotated so as to remove the arm |07 thereof frombeneath the switch actuating spring, thus releasing this spring. Whenthe spring |00 is released, the energy stored by virtue of the'stressing action of .the armature 20 of the electromagnet I2 produces asnap actuation Aof the switch mechanism 80 with the result that the`contacts 52 and 93 are rapidly and positively closed and the contacts90 and 9| are rapidly opened. When the contacts 02 and 93 are closed, aconnection is made from the line terminal Mii and through the contacts92 and e3 to the time delay load circuit |45, thus energizing thiscircuit.

inasmuch as the motor II remains energized after the time delay intervalis passed, the differential cage 3S continues to rotate in acounterclockwise direction and continues to rotate the latch i525 in theclockwise direction. As a result, the projecting arm |35 of the latch|05 is moved into engagement with the movable arm Its of the `motorswitch |20 so that the motor switch contacts are opened and the motor isdeenergized. However, since the line circuit to the terminals M0 and |4Iis still maintained, the relay coil le remains energized and the timingmechanism remains in the condition described immediately above withpower being supplied to the load |115.

When the line circuit is opened, the relay armature coil i9 isdeenergized and the armature 20 thereof moves upwardly under theinfluence of the spring 22 so as to release the ratchet pawl 'I0 fromthe ratchet wheel e3. As a result, the differential cage 33 is returnedto its initial 'position by means of the return spring 66 so that thearm @4i thereof is again in engagement with the stop arm t3 carried bythe adjustment 'wheel 55. When the relay armature 20 moves upwardly theswitch actuating spring |00 also moves in the same direction so as topermit the arm |01 of the latch member to be moved under the spring istby means of the latch return spring |09. When the latch member |05 ismoved to the spring engaging position, the arm |35 'is disengaged fromthe motor blade |30 so that the motor is again ready for energization.The time delay relay of the present invention is then ready for anothercycle of operation.

In the event Vthat vthe time delay interval is to 'be changed, theadjustment screw '551 is-rotated so as to rotate the adjustment wheel 55thereby varying the stationary position of the differential cage 38. Inthis connection, it will be understood that the diierential cage 38 ismoved at a constant rate from its initial position to the latch engagingposition under the control of the constant speed motor Accordingly, avariation in the initial position of the cage 35 provides a linearvariation of the same delay interval.

From the above description, it will be apparent that there has beenprovided a time delay relay which has numerous applications such as forturning on the plate circuit of an electron discharge valve apredetermined time after the lament current is turned on.

With the arrangement described thus far, the time delay relay repeatsits cycle following each operation thereof. In certain applications itis desirable to have an integrating time delay relay and in Fig. ll ofthe drawings there is illustrated such a modication of the presentinvention. Referring to this gure, .the time delay relay shown thereinis identical in many respects tothe time delay relay of Figs. l to l0,inclusive, and the corresponding elements of these relays have beengiven the same reference numerals. In general, the time delay relay ofFig. il embodies the features oi the present invention in an integratingtype of time delay relay wherein the relay integrates or sums upsuccessive time intervals when a circuit is closed to the line terminalsIt@ and lil! and energizes the load circuit when the desired total timedelay is reached.

More specically, the ratchet pawl 'I0 is not controlled by the relayarmature 20 as in Fig. 10 but instead is normally biased into engagementwith the ratchet wheel I3 by means of .the biasing spring |45.Accordingly, when a circuit is closed to the line terminals |00 and |5|and the motor II is energized, the ratchet wheel e3 is held stationaryand the differential cage 33 immediately begins to move in thecounterclocltwise direction to engage the latch arm H0. If the circuitto the line terminals |40 and |4| is opened momentarily, the motor I Iand the relay I2 are deenergized and movement of the diierential cage isstopped. However, the diierential cage is not returned to its startingposition upon release of the relay I2 for the reason that the pawl 'I0is continuously biased into engagement with the ratchet wheel i3 by thespring |48. The relay thus integrates or sums up the t0ta1 on periodsduring which a circuit is closed to the line terminals les and IM toobtain the desired total time delay interval. A-t the end of the totaltime delay interval the differential cage 38 again trips the latch arm 0to release the switch actuating spring |00 and close the switch contacts92 and 93 thereby closing a circuit to the time delay load circuit M5 atthe end of the predetermined time delay interval.

When the latch |05 is vtripped and the switch actuating spring |05 ismoved downwardly, the spring |00 engages the other end of the pawl I0 soas to disengage the pawl 'it from the ratchet wheel 43 and permit thedifferential cage 38 to be returned to its initial position by means ofthe spring .65. The pawl I0 is also provided with an upstanding arm |50which engages the movable contact |30 of the motor switch so that themotor is deenergized at the instant that circuit connections are made tothe time delay load circuit |45. Whenvthe main circuit is opened therelay coill I9 is deenergized and the switch actuating sprngfl 00returns to its .initial position at whichv 9 position it is Aheld bymeans'of the latch |05, the controlled circui-t |45 is deenergized, thepawl 10 again engages the ratchet wheel 43, and the motor switch |29 isclosed. The integrating relay of Fig. ll is then set up for anothercycle of operation.

There are applications where it is desirable to close a load circuitfollowing a predetermined time delay after actuation of the means forclosing the load circuit, but with additional means to vary the timedelay should another event or subsequent condition occur during the timedelay period. In Fig. 12 of the drawings, there is illustrated amodication of the present invention in which such an `arrangement forvarying the time delay can be accomplished and the construction is verysimilar .to that of the relay of Figs. l to 10 with the provision ofmeans including an additional diierential gear mechanism to introduce achange in the speed of operation oi the time delay means at variabletimes after the original time delay has started. The principle involvedin the modiiication of Fig. 12 is that transmission through adiiierential gear mechanism having a stopped cage is accomplishedwithout change of speed, but if the cage is rotated, it will increase ordecrease the velocity of transmission, depending upon the direction ofrotation thereof. Referring now to Fig. l2 wherein the correspondingparts are designated by the same reference numerals as in the precedingdrawings, the elements are substantially identical with the disclosureof Fig. l except for the provision of a second diierential gear traingenerally designated at |49, including a cage |55 very similar to thecage 3S of the differential already described -except for the provisionof a eripheral gear portion thereon, which gear train is interposedbetween the motor I! and the pinion 31. Associated with the diierentialgear train |49 is a second electromagnet |5I capable of being energizedfrom a suitable signal or power source represented by the terminals I52d and |525. The electromagnet I| is adapted to control an armature |53pivoted as indicated at |54. A spring means |55 normally biases thearmature |53 to the position shown in Fig. 12 of the drawings, but uponenergization of the electromagnet 15|, counterclockwise rotation of thearmature |53 about the pivot |54 occurs with the result that a pawlportion |51 of the armature |53 is rendered effective to engage theteeth of the cage |55 and prevent rotation thereof.

For the purpose of increasing or decreasing the speed of rotation of thepinion 31, illustrated as mounted on a shaft |58, above or below thespeed at which it would be driven through the difierenvtial gear train|49 when the cage of the gear train is held stationary, there isprovided a gear train for rotating the cage |55 comprising a gear I5|von the shaft I4 which in turn meshes with a gear 'I 62 mounted upon asuitable shaft |63. For purposes which will become apparent from thefollowing description, the gear |52 is connected to the shaft |63 by a.suitable friction clutch schematically designated at |54. The shaft |53is provided at its other Vend with a gear 65 drivingly engaged with thegear teeth formed on the periphery of the cage |55. It will beunderstood that by suitable gearing the cage |55 may be rotated ineither a clockwise or counterclockwise direction by the gear |65, butfor the illustrated embodiment the cage |50 is rotatedin the samedirection as the shaft I4. The cage |50 is rotatable about shaft |61which corresponds to the shaft 35 of the other differential gear trainalready described. Associated with the cage |55 are diierential gears|59 and |15. These differential gears are carried by the cage |55 andthe differential gear |59 meshes with a driving gear |1| attached to theshaft |51 while the differential gear |15 meshes with a driven gear |12attached to the shaft |58 to which the pinion 31 is also attachedwhereby rotation of driven gear |12 will cause similar rotation of thepinion 31. For the purpose of transmitting torque through thediierential gear train |49, the shaft I4 is additionally provided with agear |15 which meshes with the driving gear |1I.

It will be apparent that when the solenoid I5| is deenergized and themotor is energized that the pinion 31 will be driven through thedifierential gearing 159 and in addition by virtue of the rotation ofthe cage |55 the speed of rotation of pinion 31 will be different fromwhat it would be if cage |55 were held mationary. For the arrangementillustrated resulting in rotation of the cage |55 in the same Adirectionas the shafts I4 and |58, the pinion31 will rotate at a higher speedthan if cage |55 were held stationary. Obviously, by an oppositerotation of cage |55, a reduction in the speed of rotation of the pinion31 relative to its speed when the cage |55 is prevented from rotating isobtained. It will be understood that depending upon the gear ratiosemployed, the increase or decrease in speed of rotation of the pinion 31may be controlled as desired. Upon energization of the solenoid I5I,however, pawl |51 prevents rotation of the cage |55 which means thatshaft I 63 muststand still and relative rotation between the gearl|52and the shaft |53 can occur by virtue of the friction clutch |54. Underthese conditions, with the cage |50 prevented from rotating pinion 31 isdriven through the differential gearing |49 in a readily understoodmanner without change in speed relative to that of the shaft I4.Consequently, there is provided a relay which provides a time delay inaccordance with the formula t T Ai k where T is the total time delay, Ais the normal or set time delay, t is the time that elapses between theclosing of the circuit initiating the normal or set time delay and theoccurrence of the second signal energizing or deenergizing solenoid |5|,and 7c is a selected constant. A typical application of the device shownin Fig. l2 is one in which there is a normal time delay for controllinga second circuit such as a circuit connected to the terminals |15a and|1517 of the switch 80 after the main circuit to the motor I| is closedand a second signal which occurs after the main circuit closing, butbefore the time delay has elapsed modifies the time of controlling thesecond circuit in dependence upon the amount of time of the normal timedelay which has elapsed at the occurrence of the second signal. Underthese conditions the device measures the remainder of the original timedelay and modifies the subsequent delay by an amount which varies withthe remainder of the time delay which it nds. Thus, it actually works acomputation based on the time relation of the second signal to theoccurrence of the closing of the main circuit.

The operation of the device shown in Fig. l2 will readily be understoodfrom the above description. Upon closing the circuit to the lineterminals |45 and |4I, the motor is energized and drives thedifferential cage 38 through the dif'- ferential gearing |49 butmodified by virtue of the rotation of cage |50 through shaft |63. Afterthe closure of the main circuit and before the end of the normal or settime delay interval determined by the setting of element 51 and thespeed at which pinion 31 is rotated, a second circuit is closed totheterminals |5201r and |521) thus energizing the solenoid and stopping thedifferential cage l 50 whereupon the rate of rotation of thedifferential cage 38 ischanged (reduced in the illustrated embodiment)to change the total time delay interval. When the cage 38 trips thelatch member |05, a circuit to the load terminals Illia and |1519 isInodiiiedA to establish (in the illustrated embodiment) the circuitconnections to the controlled circuit. The motor is again deenergized byfurther movement of the latch |55 in a manner identical to thatdescriped in connection with the relay of Fig. and upon opening of themain line termials vand HH, the switch 80 is restored to its initialposition and the relay is reset to its -original position.

While the alternative embodiments of the time delay rel-ay of thepresent invention have been illustrated as provided with a substantiallyimmediate resetting of the differential cage 38 when the line circuit isopened, it will be understood lthat t'he differential cage may bereturned to its initial position by any suitable control means to obtaina desired resetting interval. For example, a self-starting adjustablereturn escapement may be driven from the timing shaft 35 in any one ofthe embodiments of Figs. 10, 11 and 12, so as to control the nate atwhich the differential cage is returned to its initial position underthe action of the return spring 66. The reset interval can be vari-ed insmall increments by shifting a counterweight on the end of theescapement. Also, the reset interval may be changed by large incrementsby varying the gear ratio between the timing shaft .'55 and theescalpement wheel. In this connection, it will be understood that thereset time will be substantially proportional to the time delay intervaldue to the fact that the differential cage is moved through a greaterdistance for a long time delay interval than for a short' time delayinterval.

It will also be understood that the time delay relay of the presentinvention may be utilized in a two-period, repeating cycle timer. Forexample, two time delay relays of the type shown in Figs. 1 to l0,inclusive, of the drawings can be employed to give a timing range fortwo parts of a given time cycle. Thus, aiirst time delay relay can beprovided with a cycle of twenty-four hours, and a second timer with acycle of live seconds, to use an extreme example. By connecting the tworelays in series, that is, by controlling the second relay from theswitch mechanism 80 of the nrst relay, a time delay control can beobtained once every twenty-four hours within a predetermined five secondrange. However, in order to provide such an arrangement, it is necessaryto provide a starting switch in series with the rst driving motor. Sucha two-period timing relay may also be made nonrepetitive by providing atimed oi cycle plus a timed on cycle after which the circuit locks out-until a starting switch actuated to normalize the relays.

Although the invention has been described with the differential cage asthe switch actuating element of the differential, it will be understoodthat the functions of the three elements of the diderential, namely thedriving gear, the cage, and the driven gear, may be nterchanged. Forexample, the `relay could be designed with the cage as the lockedelementy and the driven gear as the switch actuator. While there havevbeen described what are at present considered to be the preferredembodiments of the invention, it will be understood that various changesand modifications will occur to those skilled in the art and it is aimedin the appended claims to cover all such changes and modications as fallwithin the true spirit and scope of the present invention.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

l. In a time delay relay, means comprising a switch having relativelymovable switch contacts, an electric motor, differential gearingdrivingiy connected to said motor and including a nore mally stationarydilerential cage, an electromagnet having a movable armature, means forsimultaneously energizing said electromagnet and said motor, switchactuating energy storage means, means responsive to movement of saidarmature upon energization of said electromagnet for storing energy insaid energy storage means, latch means for maintaining energy stored insaid energy storage means, means for holding stationary one of the gearsof said difierential gearing whereby said diiierential cage is rotatedin a given direction in response to operation or said motor, and meansresponsive to movement of said cage to a :predetermined position fortripping said latch means thereby to release the energy stored in saidenergy storage means to actuate said switch.

2. In a time delay relay, means comprising a switch having relativelymovable switch contacts, an electric motor, differential gearingdrivingly connected to said motor and including a normally stationarydifferential cage, an electromagnet having a movable armature, means forsimultaneously energizing said electromagnet and said motor, switchactuating energy storage means, means responsive to movement of saidarmature upon energization of said electromagnet for storing energy insaid energy storage means, latch means for maintaining energy stored insaid energy storage means, means responsive to energization of saidelectromagnet for holding stationary one of the gears of saiddiiierential gearingv whereby said differential cage is rotated in agiven direction in response to operation of said motor, and meansresponsive to movement of said cage to a predetermined position fortripping said latch means thereby to release the energy stored in saidenergy storage means to actuate said switch.

3. In a time delay relay, means comprising a switch having relativelymovable switch contacts, an electric motor, differential gearingdrivingly connected to said motor and including a normally stationarydifferential cage, an electromagnet having a movable armature, means forsimultaneously energizing said electromagnet and said motor, a switchactuating spring, means responsive to movement of said armature uponenergization of said electromagnet for stressing said switch actuatingspring, latch means for restraining said switch actuating spring instressed condition, means responsive to energization of saidelectromagnet for holding sta tionary one of the gears of' saiddii'erential gearing whereby said dilerential cage is rotated in a givendirection in response to operation of said motor, and means responsiveto movement oi' said cage to a predetermined position for tripping saidlatch means thereby to release said stressed switch actuating means toactuate said switch.

4. In a time delay relay, means comprising a switch having relativelymovable switch contacts, an electric motor, differential gearingdrivingly connected to said motor and including a normally stationarydifferential cage, an electromagnet having a movable armature, means forsimultaneously energizing said electromagnet and said motor, a switchactuating spring, means responsive to movement of said armature uponenergization of said electromagnet for stressing said switch actuatingspring, latch means for restraining said switch actuating spring instressed condition, means responsive to energization of saidelectromagnet for holding stationary one of the gears of saiddifferential gearing whereby said differential cage is rotated in agiven direction in response to operation of said motor, and manuallyoperable means for adjusting the normally stationary position of saidcage thereby to vary the time delay control of said relay.

5. In a time delay relay, means comprising a switch having relativelymovable switch contacts, an electric motor, differential gearingdrivingly connected to said motor and including a normally stationarydifferential cage, an electromagnet having a movable armature, means forsimultaneously energizing said electromagnet and said motor, a switchactuating spring, means responsive to movement of said armature uponenergization of said electromagnet for stressing said switch actuatingspring, latch means for restraining said switch actuating spring instressed condition, means responsive to energization of saidelectromagnet for holding stationary one of the gears of saiddifferential gearing whereby said diiferential cage is rotated in agiven direction in response to operation of said motor, means responsiveto movement of said cage to a predetermined position for tripping saidlatch means thereby to release said stressed switch actuating means toactuate said switch, and means responsive to movement of said cagebeyond said predetermined position for deenergizing said motor.

6. In a time delay relay, means comprising a switch having relativelymovable switch contacts, an electric motor, differential gearingdrivingly connected to said motor and including a normally stationarydiierential cage, an electromagnet having a movable armature, means forsimultaneously energizing said electromagnet and said motor, a switchactuating spring, means responsive to movement of said armature uponenergization of said electromagnet for stressing said switch actuatingspring, latch means for restraining said switch actuating spring instressed condition, means responsive to energization of saidelectromagnet for holding stationary one of the gears of saiddifferential gearing whereby said dierential cage is rotated in a givendirec tion in response to operation of said motor, means responsive tomovement of said cage to a predetermined position for tripping saidlatch means thereby to release said stressed switch actuating means toactuate said switch, means responsive to movement of said cage beyondsaid predetermined position for deenergizing said motor, and meansresponsive to deenergization of said 'electromagnet forV returning bothsaid cage and said latch means in their responsive? initial positions.

7. In a time delay relay, means comprising a switch having relativelymovable switch contacts, an electric motor, diierential gearingdrivingly connected to said motor and including a normally stationarydifferential cage, an electromagnet having a movable armature, means forsimul taneously energizing said electromagnet and said motor, a switchactuating spring, means responsive of movement of said armature uponenergization of said electromagnet for stressing said switch actuatingspring, latch means for restraining said switch actuating spring instressed condition, means responsive to energization of saidelectromagnet for holding stationary one of the gears of saiddifferential gearing whereby said differential cage is rotated in agiven direction in response to operation of said motor, means responsiveto movement of said cage to a predetermined position for tripping saidlatch means thereby to release said stressed switch actuating means toactuate said switch, means responsive to movement of said cage beyondsaid predetermined position for deenergizing said motor, meansresponsive to deenergization of said electromagnet for returning bothsaid cage and said latch means to their respective initial positions,and escapement means connected to said differential cage for controllingthe return time thereof.

8. A time delay relay, comprising a constant speed electric motor,differential gearing driven by said motor and including a diiferentialcage carrying a pair of relatively fixed differential gears, anelectromagnet having a movable arma# ture, said armature carrying aswitch actuating spring, switch means adapted to be actuated by saidspring, latch means for normally holding said springv in stressedposition following opera tion of said electromagnet, means controlled bysaid armature for restraining the driven gear of said differentialgearing whereby said differential cage is rotated in a given direction,and means carried by said differential cage for tripping said latchmeans after a predetermined rotation of said cage thereby to releasesaid spring and actuate said switch means.

9. A time delay relay comprising a switch having relatively movableswitch contacts, a constant speed electric motor diiferential gearingdrivingly connected to said motor and including a normally stationarydiiierential cage carrying a pair of differential gears and a drivengear, an electromagnet having a movable armature, switch actuatingenergy storage means, means responsive to movement of said armature uponenergization of said electromagnet for storing energy 1in said energystorage means, latch means for maintaining energy stored in said energystorage means, means responsive to energization of said electromagnetfor holding stationary said driven gear whereby said dierential cage isrotated from an initial position to a tripping position at a speeddetermined by said constant speed electric motor, and means carried bysaid cage for tripping said latch means when said cage reaches saidtripping position thereby to release the energy stored in said energystorage means to actuate said switch.

10. A time delay relay comprising a switch having relatively movableswitch contacts, a constant speed'electric motor, differentialgearing'rdrivingly connected :tosaid motor and including a normallystationary differential cage carrying a pair of diirerential gears andadriven gear, an electromagnet having a movable armature, a switchactuating spring, means responsive to movement of said armature uponenergization of said electromagnet for stressing said spring, latchmeans for maintaining said spring in a stressed condition, meansresponsive to energization of said electromagnet for holding stationarysaid driven gear whereby said differential cage is rotated from vaninitial position to a tripping position at a speed determined by saidconstant speed electric motor, means carried by said cage for trippingsaid latch means when said cage reaches said tripping position therebyto release said .Spring` and permit it to actuate said switch, meanscontrolled by said latch means for deenergizing said motor apredetermined time interval after said cage reaches said trippingposition, and spring means for restoring said cage and latch means totheir initial positions upon deenergization of said electromagnet.

11. A time delay relay comprising a switch having relatively movableswitch contacts, a constant speed electric motor, differential gearingVdrivingly connected to said motor and including ya normally stationarydifferential cage carrying a pair of differential gears and a drivengear, an electromagnet having a movable armature, a switchv actuatingspring, means responsive to movement of said armature upon energizationof said electromagnet for stressing said spring, latch means formaintaining said spring in a stressed condition, means responsive toenergization of said electromagnet for holding stationary said drivengear whereby said differential cage is rotated from an initial positionto a tripping position at a speed determined by said constant speedelectric motor, means carried by said cage for tripping said latch meanswhen said cage reaches said tripping position thereby to release saidspring and permit it to actuate said switch, means controlled by saidlatch means for deenergizing said motor a predetermined time intervalafter said cage reaches said tripping position, spring means forrestoring said cage and latch means to their initial positions upondeenergization of said electromagnet, and manually operable means foradjusting said initial position of said cage thereby to control the timedelay of said relay.

12. A time delay relay comprising a switch having relatively movableswitch contacts, a constant speed electric motor, differential gearingdrivingly connected to said motor and including a normally stationarydifferential cage carrying a. pair of differential gears and a drivengear, an electromagnet having a movable armature, a switch actuatingspring, means responsive to movement of said armature upon energizationof said electromagnet for stressing said spring, latch means formaintaining said spring in a stressed condition, means independent ofsaid electromagnet for holding stationary said driven gear whereby saiddiierential cage is rotated from an initial position to a trippingposition at a speed determined by said constant speed electric motorimmediately upon energization thereof, means carried by said cage fortripping said latch means when said cage reaches said tripping positionthereby to release said spring and permit it tol actuate said switch,means controlled by said latch means for deenergizing said motor apredetermined time interval after said cage reaches said trippingposition, and spring 16 means for restoring said cage and latch means totheir initial positions upon deenergization of said electromagnet.

13. A time delay relay, comprising an electric motor, differentialgearing driven by said motor and including a normally stationarydiiierential cage, an electromagnet having a movable armature, means forenergizing both said electromagnet and said motor, an electric switch, aswitch actuating spring carried by said armature and tending to movetherewith, latch means for restraining said spring whereby upon movementof said armature said spring is stressed in response to energization ofsaid electromagnet, means for normally holding stationary one of thegears of said differential gearing independently of the operation ofsaid electromagnet whereby said diiierential cage is rotated in a givendirection during periods when said motor is energized, meansv responsiveto movement or said cage to a predetermined position for tripping saidlatch means thereby tc release said spring and actuate said switch, andmeans actuated by said spring simultaneously with actuation of saidswitch for deenergizing said motor and releasing said gear holdingmeans, thereby to permit said cage to return to its initial position.

14. A time delay relay, comprising an electric motor, differentialgearing driven by said motor and including a normally stationarydifferential cage, an electromagnet having a movable armature, means forenergizing both said electromagnet and said motor, a switch, a switchactuating spring carried by said armature, latch means for restrainingsaid spring whereby said armature stresses said spring when saidelectromagnet is operated to move said armature, means for holdingstationary one of the gears of said differential gearing whereby saiddidierential cage is rotated in a given direction, means responsive tomovement of said cage to a predetermined position for tripping saidlatch means thereby to release said spring and actuate said switch, andmeans controllable independently of said electromagnet for changing therate of rotation of said differential cage foliowing initial movementthereof thereby to change the time delay interval of said relay independence upon the operation of said last mentioned means.

15. A time `delay relay, comprising an electric motor, diierentialgearing by said motor and including a normally stationary ferentialcage, an electromagnet having a mevable arrnature, means for energizingboth said electromagnet and said motor, a switch, a switch actuatingspring carried by said armature, latch means for restraining said springwhereby said armature stresses said spring' when said electromagnet isoperated to move said armature, means responsive to energization or"said electromagnet for holding sttionary one of the gears of saiddiierential gearing whereby said differential cage is rotated in a givendirection, means responsive to movement of said cage to a predeterminedposition for tripping said latch means thereby to release said springand actuate said switch, and means controllable independently of saidelectromagnet for changing the rate of rotation of said diierential cagefollowing initial movement thereof thereby to change the time,r delayinterval of said relay in dependence upon the operation of said lastmentioned means.

16. A time delay relay, comprising an electric motor, differentialgearing driven by said motor and including a normally stationarydifferential cage, an electromagnet having a movable armature, means forsimultaneously energizing both said electromagnet and said motor, aswitch, a switch actuating spring carried by said armature, latch meansfor restraining said spring to prevent actuation of said switch whensaid latch means is effective whereby said armature stresses said springwhen said electromagnet is operated, means for holding stationary one ofthe gears of said differential gearing whereby said differential cage isrotated in a given direction, means including a second differential geartrain interposed between said motor and said differential gearing andcontrollable independently of said energizing means for changing therate of rotation of said cage, and means responsive to movement of saidcage to a predetermined .position for tripping said latch means therebyto release said spring.

17. A time delay relay, comprising an electric motor, first differentialgearing driven by said motor and including a normally stationary firstdifferential cage, an electromagnet having a movable armature, means forenergizing both said electromagnet and said motor, a switch, a switchactuating spring carried by said armature, latch means for restrainingsaid spring from actuating said switch whereby said armature stressessaid spring when said electromagnet is energized, means for holdingstationary one of the gears of said rst differential gearing wherebysaid first differential cage is rotated in a given direction, a seconddifferential gear train including a second differential cage andconnected between said driving motor and said first differentialgearing, solenoid means adapted to be energized after said electromagnetis operated and independently of said energizing means for controllingthe movement of said second differential cage thereby to vary the rateof rotation of said rst differential cage. and means responsive tomovement of said rst differential cage to a predetermined position fortripping said latch means thereby to release said spring and actuatesaid switch.

18. A time delay relay, comprising an electric motor, first differentialgearing driven by said motor and including a normally stationary firstdifferential cage, an electromagnet having a movable armature, means forenergizing both said electromagnet and said motor, a switch, a switchactuating spring carried by said armature, latch means for restrainingsaid spring from actuating said switch whereby said armature stressessaid spring when said electromagnet is energized, means for holdingstationary one of the gears of said first differential gearing wherebysaid rst differential cage is rotated in a given direction, a seconddifferential gear train including a second differential cage andconnected between said driving motor and said rst diferential gearing, aratchet dened on the :periphery of said second cage, solenoid meansadapted to be energized after said electromagnet is operated andindependently of said energizing means including a pawl for engagingsaid ratchet for controlling the movement of said second differentialcage thereby to vary the rate of rotation of said rst differential cage,and means responsive to movement of said first differential cage to apredetermined position for tripping said latch means thereby to releasesaid spring and actuate said switch.

19. A time delay relay, comprising an electric motor, differentialgearing driven by said motor and including a normally stationarydifferential cage, an electromagnet having a movable armature, means forenergizing both said electromagnet and said motor, an electric switch, aswitch actuating spring carried by asid armature and tending to movetherewith, latch means for restraining said spring whereby upon movementof said armature said spring is stressed in response to energization ofsaid electromagnet, means for normally holding stationary one of thegears of said differential gearing independently of the operation ofsaid electromagnet whereby said differential cage is rotated in a givendirection during :periods when said motor is energized, said gearholding means preventing reverse rotation of said cage upondeenergization of said motor providing said cage has failed to move to apredetermined position, means responsive to movement of said cage tosaid predetermined position for tripping said latch means thereby torelease said spring and actuate said switch, and means actuated by saidspring simultaneously with actuation of said switch for deenergizingsaid motor and releasing said gear holding means, thereby to permit saidcage to return to its initial position.

20. In a time delay relay means comprising an electric switch, anelectric motor, differential gearing drivingly connected to said motor,an electro-magnet having a movable armature, means for energizing saidelectro-magnet and said motor, switch actuating energy storage means,means responsive to movement of said armature upon energization of saidelectro-magnet for storing energy in said energy storage means, latchmeans for maintaining energy stored in said energy storage means, meansfor holding stationary one of the elements of said differential gearingwhereby a second element of said differential gearing is rotated in agiven direction in response to operation of said motor, and meansresponsive to movement of said second element to a predeterminedposition for tripping said latch means thereby to release the energystored in said energy storage means to actuate said switch.

ARTHUR B. POOLE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,937,391 Schwegler Nov. 28, 19332,130,405 Andrews Sept. 20, 1938 2,312,077 Cowles Feb. 23, 19432,388,686 Mabig Nov. 13, 1945 2,496,310 Rabinow Feb. 7, 1950 2,526,445Young Oct. 17, 1950

